A stator is a stationary part of an electric machine, such as a generator or motor. In a generator, current can be induced in the stator coils by the influence of the rotor's rotating field coils. A stator coil in a small electric machine can be made from wire coils that are wrapped in an arrangement to form a cylindrical frame for surrounding the rotor. The wire is usually coated with an insulating lacquer so that adjacent coil windings do not short circuit with one another. In large industrial generators, however, the stator winding must carry a large amount of current, and are therefore, usually made from elongated bars of copper, for example. The stator bars are bent or formed into specific, complex shapes, and multiple pairs of approximately mirror-imaged stator bars usually are arranged in a cylindrical array and electrically connected to create loops for which the rotor field coil can induce currents. One of the challenges in building or refurbishing an electrical generator is the bending or forming of the stator bars into the correct shape so that the array can be assembled quickly, and so that the correct spacing tolerance is maintained between each of the stator bars.
Stator bars can be subject to high voltage potentials during the operation of the electric machine, and may arc under certain conditions. Arcing is a particular problem in certain sections of the stator bar, particularly where the stator bar is bent and where high electric field strengths are present. Insulation material can be utilized to wrap or coat the stator bars to allow the stator to be run at higher potentials without arcing. However, small gaps, bubbles, and/or imperfections in the insulation can reduce the effective dielectric constant of the insulation and lead to arcing, damage, and failure of the stator bar and electrical machinery.